408 CONTRIBUTIONS FROM THE NATIONAL HERBARIUM. 
IT can not, however, from the insufficient fragment before me be certain about it. 
The leaves are shorter and rather more rigid than in that species. 
Eutriana bromoides Trin. Gram. Unifl. 241. 1824, not Kunth 1833. It is more than 
probable that the species to which Trinius applied this name is B. americana, although 
the first synonym cited is Atheropogon bromoides Roem. & Schult. The other two 
synonyms are Aristida americana L.and Bouteloua litigiosa Lag., and the plant described 
is from the West Indies. Kunth @ has in effect expressed the same view. 
Bouteloua elatior Griseb. Fl. Brit. W. Ind. 537. 1864. A portion of the type, Wull- 
schlagel 619 and 660, Antigua, in the Grisebach Herbarium, and a photograph are 
before me. It is typical of Aristida americana L. 
Atheropogon americanus Fourn, Mex. Pl. 2: 139.1881. Based upon Aristida ameri- 
cana L. 
Bouteloua triathera Benth. Journ. Linn. Soc. Bot. 19: 104. 1881. Presumably based 
on Triathera americana Desv. 
Bouteloua americana Scribn. Proc. Acad. Phila. 1891: 306.1891. Scribner bases 
this name on ‘‘ Aristida americana Sw. Obs. 41. t. [2.] f. 2. (1791)’’, on the supposition 
that this was distinct from A. americana L., citing Munro’s statement, that the 
Linnxan A. americana was a true Aristida and the species named Aristida dispersa 
by Trinius. But, as has been shown, Linnzus’s type specimen is a Bouteloua. 
Swartz does not give this as one of his own species, but gives a reference that leads to 
Linneeus’s species. Swartz’s illustration shows that he correctly interpreted the 
species. Hence Scribner’s name is, in the last analysis, based on Aristida americana L. 
DESCRIPTION. 
A spreading, ascending, or etect, smooth annual; flowering culms mostly erect, 
freely branched, 20 to 80 cm. high; sheaths striate, smooth, short, close; blades nar- 
row, involute, acuminate, bearing numerous papillose hairs on the edges toward the 
base, there merging into the very narrow ligular ring; spikes about 2 cm. long, very 
lax, 3 to 6 or 7; spikelets 5 to 7, about 3 mm. apart, not pectinate but loose, and lying 
at a narrow angle with the rachis; glumes pronouncedly keeled and strongly hispid, 
rather abruptly acuminate, the first about 3 mm., the second about 4 mm. long; 
lemma smooth, shining, and bone-like on the back, 3-awned, the lateral awns less than 
1mm. long, the central projecting about 2 mm, farther; palet 2-nerved, with 2 short 
awns, nearly as long as its lemma; rudiment consisting of a modified lemma of 3 awns 
about 9mm. long, united into a hard small scale at the base and faced by a small 
2-nerved rudimentary palet; caryopsis not seen. (F1GuRE 57.) 
The group comprising Bouteloua americana and the five species here following is a 
very difficult one and a greatsmany names have been applied to the different species 
owing to a difference of opinion among authors as to generic and specific limitations 
and to the disregard of the principle of priority as well as to a misunderstanding or 
neglect of the earlier descriptions. 
Bouteloua radicosa as interpreted here is fairly well marked off. It is a large, 
robust, almost woody based plant with wide, strongly papillose-hairy leaves. Bou- 
teloua repens as here interpreted is not so common as has been supposed. It is easily 
recognized by its glaucous aspect and by its lack of papillose hairs. The species 
appears to be confined to the Pacific coast region of central and southern Mexico. 
Bouteloua americana also is well characterized by its narrow spikes and annual 
habit. 
It is B. filiformis and B. heterostega that present the greatest difficulties. They are 
very difficult to segregate, but that is simply another way of acknowledging that we 
do not know the species well enough. 
4 Enum. Pl. 1: 281. 1833, under F. bromozides. 
b See above under Aristida americana L. 
